As is well known, silicone polymers are different from other organic polymers and have particular characteristics. For instance, rubbers of silicone polymers are characterized in that they can maintain rubber elasticity for a long period of time even under a high temperature condition. They do not lose this rubber elasticity even when exposed to a low temperature condition of -70.degree. C. Additionally, temperature dependent fluctuation of the rubber property is small. In addition, they show stable electric characteristic values in a broad temperature range, and they have excellent arc resistance, corona resistance, and weather durability. Accordingly, even when they are exposed outdoors for a long period of time, or exposed to ultraviolet light, or exposed to ozone the rubber property thereof is not deteriorated. As silicone polymers have excellent characteristics as rubber elastic materials, as mentioned above, they have been put the practical use in various industrial fields and have been evaluated as indispensable and important materials therein.
However, silicone polymers are inferior to any other organic polymers in terms of mechanical strength. For instance, room temperature vulcanizing (hereinafter RTV) silicone rubber compositions are used in construction of outer walls of buildings, but they are not used as a structural material because of the weak rubber strength and are, therefore, exclusively used as a sealant material. Accordingly, silicone rubbers are not used as general resins or engineering plastics because of this poor mechanical strength. Such silicone rubbers, therefore, have a drawback in that they can be used only for limited, particular uses.
RTV silicone rubber compositions are used as a sealant of a non-shaped gasket for car engine parts because of the in-situ shapability thereof. In addition, for compositions are also significantly evaluated from the viewpoint of the excellent storage stability, operability, sealability, and heat resistance. However, they do not have sufficient oil resistance, and the cured product has been found to cause oil leakage when used in conjunction with gear oil containing a large amount of additives. Such oil leakage is a problem in this technical field.
The RTV silicone rubber compositions have the characteristic of changing into an elastomer upon contact with moisture at room temperature. However, as they are cured after being hydrolyzed with the moisture in air, they are required to be exposed to air so as to be cured. Accordingly, a long time is necessary before the composition is completely cured, and, if the composition is not exposed to air, no curing will take place. Thus, the composition still has such problems.
For such drawbacks of silicone rubbers, JP-A-59-80463 (the term "JP-A" as used herein means an "unexamined, published Japanese patent application") mentions a means of improving only the oil resistance of the materials, and JP-A-60-219284 mentions a means of improving the oil resistance of the materials and lowering the elasticity thereof. However, each of these are silent on the means of elevating the mechanical strength of the cured products as well as on the means of obtaining silicone rubber materials curable under moisture-free conditions.